Many different types of seed closing wheels are presently commercially available, some of which are especially designed to handle particular kinds of soil conditions. Some conventional wheels are designed to apply converging pressure outside the sidewalls of the seed furrow so as to push or squeeze the sidewalls together, essentially “sandwiching” the seeds between opposite faces of the sidewalls. However, in high moisture situations this can be problematic because as the soil dries out, it tends to contract, sometimes causing the slit between the two sidewalls to open up and expose the seeds.
More recently, closing wheels with radially extending spikes have been utilized in an effort to break down the sidewalls of the furrow and crumble the soil so that there is less of a defined slit in the soil that is subject to opening up as the soil dries out. However, spiked closing wheels present their own unique problems, including some tendency to be overly aggressive and penetrate the soil too deeply in certain conditions, disturbing and sometimes dislodging the seeds as the teeth lift out of the soil at the rear of the wheels. Another problem is that substantial gaps are typically presented between the spikes around the wheel such that the spikes themselves only intermittently engage the soil, perhaps where no seed is located. This can result in improper or incomplete covering of the seeds, which leads to uneven emergence and lost yield.
The present invention is directed to a closing wheel that achieves a highly desirable fragmentizing of the seed furrow sidewalls above the seeds and squeezing together of the sidewalls around the seeds without disturbing the seeds themselves, thus avoiding the disadvantages of current spiked tooth wheels and other conventional designs. Among other things, the closing wheel of the present invention is also designed to be more effectively usable in a wider variety of field conditions than in the past, thereby enabling the farmer to run the same wheel in almost all conditions and avoiding the time-consuming and laborious task of changing out all the wheels on the machine to match the particular field conditions at hand.